scholarly journals Role of band structure and local-field effects in the low-energy collective electronic excitation spectra of 2H-NbSe2

2012 ◽  
Vol 86 (3) ◽  
Author(s):  
M. N. Faraggi ◽  
A. Arnau ◽  
V. M. Silkin
Keyword(s):  
Band Structure ◽  
Local Field ◽  
Electronic Excitation ◽  
Low Energy ◽  
Excitation Spectra ◽  
Field Effects

scholarly journals Роль состояний переноса заряда "лиганд-металл" в процессах возбуждения люминесценции индолкарбоксилатов европия

2022 ◽  
Vol 130 (1) ◽  
pp. 121
Author(s):  
В.И. Царюк ◽  
К.П. Журавлев
Keyword(s):  
Excitation Energy Transfer ◽  
Electronic States ◽  
Decisive Role ◽  
Low Energy ◽  
Excitation Spectra ◽  
Metal Charge ◽  
Ternary Compounds ◽  
Aromatic Carboxylates ◽  
Metal Charge Transfer

The luminescence excitation energy transfer in europium and terbium indole-3-carboxylates, indole-3-acetates and indole-3-propionates as well as ternary indolecarboxylates containing 1,10-phenanthroline and 2,2'-bipyridine molecules have been studied. The luminescence excitation spectra, the lifetimes of the 5D0 (Eu3+) and 5D4 (Tb3+) states, and the luminescence intensity are analyzed. The decisive role of ligand-metal charge transfer (LMCT) states in the quenching of the luminescence of europium aromatic carboxylates containing a π-excessive pyrrole or indole fragment is demonstrated. Most europium compounds are characterized by quenching due to the depopulation of the 5D0 state of the Eu3+ ion through the low-energy LMCT state. But in some ternary compounds, the LMCT state being of higher energy participates in the nonradiative depopulation of the excited electronic states of the ligand.

Excitation spectra of cubic perovskite titanates

2021 ◽  
Vol 32 ◽  
Author(s):  
Hieu Nguyen-Truong
Keyword(s):  
Density Functional Theory ◽  
Local Field ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Plasmon Mode ◽  
Time Dependent ◽  
Excitation Spectra ◽  
Functional Theory ◽  
Field Effects ◽  
Dependent Density

We calculate excitation spectra of cubic perovskites ATiO3 (A = Ca, Sr, Ba, Pb). The calculations are performed within the time-dependent density functional theory, including local field effects. The theoretical calculations show that the perovskites have a plasmon mode at around 12 eV, which is not observed in experiments.

Electronic excitation of benzene by low energy electron impact and the role of higher lying Rydberg states

2021 ◽  
Vol 75 (12) ◽  
Author(s):  
Alan Guilherme Falkowski ◽  
Romarly F. da Costa ◽  
Fábris Kossoski ◽  
Michael J. Brunger ◽  
Marco A. P. Lima
Keyword(s):  
Electron Impact ◽  
Electronic Excitation ◽  
Rydberg States ◽  
Low Energy ◽  
Energy Electron ◽  
Low Energy Electron

The Role of Local Fields in the Optical Properties of Silicon Nanocrystals

2006 ◽  
Vol 958 ◽  
Author(s):  
Fabio Trani ◽  
Domenico Ninno ◽  
Giovanni Cantele ◽  
Giuseppe Iadonisi
Keyword(s):  
Optical Properties ◽  
Local Field ◽  
Silicon Nanocrystals ◽  
Tight Binding ◽  
Visible Spectral Range ◽  
Local Fields ◽  
Strong Suppression ◽  
Field Effects ◽  
Dielectric Model

ABSTRACTIn this paper we discuss the role of local fields in the optical properties of silicon nanocrystals. Using a semiempirical tight binding approach, local field effects are included into the linear response theory, going beyond the standard independent particle approximation. The results show that local field effects give an important contribution to the optical properties of silicon nanocrystals, leading to a strong suppression of the absorption in the visible spectral range. This effect is attributed to the classical surface polarization contribution. A comparison between the atomistic tight binding approach and a classical dielectric model shows that the dielectric model gives reasonable results not only for large, but even for small silicon nanocrystals.

scholarly journals Influence of TOPO and TOPO-CdSe/ZnS Quantum Dots on Luminescence Photodynamics of InP/InAsP/InPHeterostructure Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 640
Author(s):  
Artem I. Khrebtov ◽  
Vladimir V. Danilov ◽  
Anastasia S. Kulagina ◽  
Rodion R. Reznik ◽  
Ivan D. Skurlov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excited States ◽  
Molecular Beam ◽  
Surface Passivation ◽  
Low Energy ◽  
Trioctylphosphine Oxide ◽  
Reverse Transfer ◽  
Semiconductor Heterostructure ◽  
Ligand Type

The passivation influence by ligands coverage with trioctylphosphine oxide (TOPO) and TOPO including colloidal CdSe/ZnS quantum dots (QDs) on optical properties of the semiconductor heterostructure, namely an array of InP nanowires (NWs) with InAsP nanoinsertion grown by Au-assisted molecular beam epitaxy on Si (111) substrates, was investigated. A significant dependence of the photoluminescence (PL) dynamics of the InAsP insertions on the ligand type was shown, which was associated with the changes in the excitation translation channels in the heterostructure. This change was caused by a different interaction of the ligand shells with the surface of InP NWs, which led to the formation of different interfacial low-energy states at the NW-ligand boundary, such as surface-localized antibonding orbitals and hybridized states that were energetically close to the radiating state and participate in the transfer of excitation. It was shown that the quenching of excited states associated with the capture of excitation to interfacial low-energy traps was compensated by the increasing role of the “reverse transfer” mechanism. As a result, the effectiveness of TOPO-CdSe/ZnS QDs as a novel surface passivation coating was demonstrated.

The role of an energy-dependent inner potential in quantitative low-energy electron diffraction

2000 ◽  
Vol 458 (1-3) ◽  
pp. 155-161 ◽  
Author(s):  
S Walter ◽  
V Blum ◽  
L Hammer ◽  
S Müller ◽  
K Heinz ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Low Energy ◽  
Energy Electron ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Energy Dependent

scholarly journals The role of electric field, peripheral chains, and magnetic effects on significant 1H upfield shifts of the encapsulated molecules in chalcogen-bonded capsules

2021 ◽  
Vol 23 (35) ◽  
pp. 19647-19658
Author(s):  
Demeter Tzeli ◽  
Ioannis D. Petsalakis ◽  
Giannoula Theodorakopoulos ◽  
Faiz-Ur Rahman ◽  
Yang Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Chemical Shifts ◽  
Electric Field Effects ◽  
Magnetic Effects ◽  
Field Effects ◽  
Equal Importance

Significant 1H upfield chemical shifts of the guests in the capsules are consequences of polarizability of chalcogens, electric field effects and peripheral chains. The effects of the electric field and of magnetic field are of equal importance.

Low-energy excitation spectra of the system KY(MoO4)2-KEr(MoO4)2

1996 ◽  
Vol 46 (S5) ◽  
pp. 2687-2688
Author(s):  
Vladimir I. Kut'ko ◽  
Nina M. Nesterenko ◽  
Yuriy N. Kharchenko
Keyword(s):  
Low Energy ◽  
Excitation Spectra ◽  
Energy Excitation
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